Completely reinstalled Fedora 10 and mpich2 source. Here is the console output when I tried "make test_barriers". This is preventing passage past the compile step. pthreads does indeed appear to be installed. /usr/lib/libpthread.a exists.

[root@hack02 Download]# ls
mpich2-1.1  mpich2-1.1.tar.gz  tmp-mpich2
[root@hack02 Download]# cd mpich2-1.1
[root@hack02 mpich2-1.1]# ls
CHANGES        doc              mpich2.def         README               RELEASE_NOTES
confdb         examples         mpich2-doxygen.in  README.developer     src
configure      maint            mpich2.sln         README.romio         test
configure.in   Makefile.in      mpich2s.vcproj     README.testing       winconfigure.wsf
contrib        Makefile.sm      mpich2.vcproj      README.winbin.rtf    www
COPYRIGHT      makewindist.bat  mpi.def            README.windeveloper
COPYRIGHT.rtf  man              mpi.vcproj         README.windows
[root@hack02 mpich2-1.1]# cd src/openpa/test
[root@hack02 test]# make test_barriers
cc     test_barriers.c   -o test_barriers
In file included from test_barriers.c:15:
opa_test.h:8:28: error: opa_primitives.h: No such file or directory
test_barriers.c:44: error: expected specifier-qualifier-list before ‘OPA_int_t’
test_barriers.c: In function ‘test_barriers_sanity’:
test_barriers.c:80: error: ‘OPA_int_t’ undeclared (first use in this function)
test_barriers.c:80: error: (Each undeclared identifier is reported only once
test_barriers.c:80: error: for each function it appears in.)
test_barriers.c:80: error: expected ‘;’ before ‘a’
test_barriers.c:87: error: ‘a’ undeclared (first use in this function)
make: *** [test_barriers] Error 1